Carburetor



June 7, 1932.

CARBURETOR Filed July: 25, 1929 s Sheets-Sheet 1 R. F. BRACKE 1 ,861,782

June 7, 1932. R F BRAC E 1,861,782

CARBURETOR Filed July 25, 1929 3 Sheets-Sheet 2 R. F. BRACKE June 7, 1932.

GARBURETOR Filed July 25, 1929 s sheets-sheet 3 v EEiEWN vii.

Patcnted June 7, 1932 ROBERT F. BRACKE, OF CHICAGO, ILLINOIS,

' ILLINOIS,

Application filed July 25,

My invention relates to improvements in carburetors and more particularly to carburetors of the fuel lift type. I

An object of the invention is to provide an improved carburetor. 1

A further object is to provide .a carburetorwherein novel mechanism is employed for assuring an ample supply of fuel to the fuel Venturi nozzle during acceleration.

Another object is 'to provide a carburetor embodying a choke and dash control of sim-' ple and highl eflicient design.

A further Ject is to provide a carburetor wherein a flexible diaphragm is employed to Fig. 4 is a sectional view along the line 44ofFig. 3;

Fig. 5 is a view along the line 55 of Fig. 1 in elevation; i

Fig. 6 is a sectional view along the line 66 of Fig. 1;

Fig. 7 is a sectional view along the line 77uof Fig. 1;

Fig. 8 is a sectional view along the line 88 of Fig. 4; and

Fig. 9 is a sectional view of amotor vehicle equipped with my improved carburetor.

advantages will herein- The carburetor selected for illustration herein is of a fuel lift type, the structure and operation of which is fully disclosed and described in its principal features in my co pending application for patent on carburetors, bearing Serial No. 311,646 and filed October 10, 1928.

Briefly the carburetor comprises an induction chamber A adapted for communication UNITED STATES PATENT OFFICE ASSIG-NOR TO CURTIS B. CAMP, OI? GL ENCOE,

TRUSTEE CABIBUBETOR 1929. Serial No. 880,791.

by its throat B with the intake manifold C of an internal combustion engine D. p A spring pressed air valve E serves to control and maintain substantially constant depression in the chamber A by controlling communication between the chamber and the principal air inlet orifice F.

r A fuel nozzle G in the form of a Venturi tube extends through a, wall of the chamber A, its inlet orifice exposed to the atmosphere and its discharged orifice centrally located within the chamber. As is well known in the art, a Venturi nozzle of this type possesses the property of creating suction at its throat H several times greater than that to which the inlet orifice is subjected during operation. This characteristic of the Venturi nozzle is utilized to lift fuel from a low level supply tank J usually located at the rear of the vehicle, (see Fi 9).

The throat municates with the interior of a fuel chamber K, which chamber receives it supply of fuel from the low level supply tank J, through a fuel valve L. The valve L is actuated by of the Venturi nozzle comtion of depression of the fuel chamber K from the throat of the Venturi nozzle G. A

diaphragm M serves this purpose, one face of which is subjected to atmospheric pressure and the other face of which forms the ceiling of the fuel chamber K. It is thus apparent that the quantity of fuel; admitted through the valve L will depend upon the demand of the Venturi nozzle G therefor.

A disc-check valve N is disposedin the fuel conducting passage beneath the valve L to prevent the back-flow of J at such times as when the speed ofthe motor vehicle is accelerated sufliciently to cause back suction in the fuel line P, due to the inertia of the fuel therein.

The structure thus far described in itself forms no part of my present invention, ex-

cept insofar as it may cooperate with the subject matter hereafter described.

My improved carburetor provides automatic means for momentarily supplying an increased fuel discharge to the induction chamber A upon the sudden falling of en gine suction, which may be due either to increased engine load or the sudden opening of the fuel mixture throttle valve R, and if height of the reservoir, leaving an air suc- 'the fuel level in the tion above the fuel to assure the immediate withdrawal of the fuel through the valve L when the valve N is closed see Fig. 6). This level of the fuel is maintained by a small air Venturi tube 11 extending through a wall of the chamber A, the throat of which communicates through a highly restricted passage 12 with the reservoir 10 at the predetermined fuel level.

Aside from maintaining reservoir 10 the venturi with its restricted passage .12 functions to maintain a condition of depression in the reservoir which results in the elimination of air bubbles existing in the fuel that might otherwise eventually reach the fuel nozzle G to cause erraticcarburetor operat1on.-

I have thus shown how the reservoir 10 serves to constantly maintain a reserve supply of fuel for use when fuel flow cannot be induced through the valve end and which is suflicient to satisfy the demand of an automatic accelerating fuel device associated therewith.

This accelerating device is described and illustrated per se in a patent on carburetors,

No. 1,831,840, issued Nov. 17, 1931, of which I am a joint inventor.

.The, accelerati'n mechanism comprises a chamber 15 (see Flg. 7) which communicates with an aindash-pot 16 through a normally closed valve 17. The dash-pot 16 houses a dash-pot piston 18 associatedwith the lowermost end of the stem 19 of valve E. The primaryv purposeof the dash-pot and piston is to stabilize the action of the air valve E so that tendency of'the valve to flutter is overcome. Under normal conditions the dashpot 16 is subjected to atmospheric pressure y the air-bleed existing about the stem 19.

' w The valve 17 has a stem 20 which extends extends downwardly the chamber 15about the upwardlyv into a cylinder bore 21 having a piston 22 disposed therein and lies with its uppermost end normally just clear of the inner end of thepiston. A depending skirt 23 from the upper wall of stem 20 to a point just below the upper end 24 of a fitting, the lower end of which forms a seat for th'e'valve 17. A spring'25 functions to-maintain the valve 17 in its normally closed position. An other spring 27 within the piston 22 maintains the piston in that position shown in Fig. 7.

vide an adequate quantity movement of the air valve E is allowed to tial in depression at opposite sides of the piston 22 will cause the piston to recede downwardly, thus opening valve'17 which action of the valve permits the communication of the relatively high depression in chamber 15 to the air dash-pot 16' below the piston 18. The difierential between atmospheric pressure above the piston 18 and the immediately communicated depression beneath the piston will cause the air valve to be drawn downwardly, thus momentarily increasing depres-, sion within the chamber A, so that an increase in fuel discharge from the 'Venturi nozzle G is brought about.

At such times as when mechanism is caused to operate by a sudden opening of the valve 7 R, accompanied by marked increase in vehicle motion and the closing of the valve N by back suction caused by inertia caused by the pipe .P, the fuel reservoir 10 functions simultaneously to prosump'tion during the accelerating period.

The joint operation of accelerating mechanism and fuel reservoirthus efliciently affords rapid and smooth acceleration of the vehicle whether from a dead standstill or from an intermediate speed, in a mannerheretofore unattained.

the accelerating of fuel for con- Another feature of my improved carburetor comprises a choke and dash control of unusual simplicity of design, which cooperates in its action with the air valve Ed the carburetor tolimit or restrain the opening independently or dependent, in part, at will upon engine lSJuctiXn communicated to the induction cham- This choke and dash control (see Figs. 5 and 8) consists of a shaft 35 extending through the induction chamber A and mountedfor rotation. The shaft 35 has a shoe 36 securedtheretowhich when moved to the po sition shown in dotted lines in Fig. 8 serves to prevent the opening of the valve E when the shaft 35 is held against movement or to limit the opening of the valve if the shoe slightly clear the valve, and to yieldingly resist opening of the valve where the shaft 35 is but yieldingly held in its adjusted position as by a spring.

These functions of the shoe 36 are brought about by mechanism best illustrated in Figs. 4 and 5 which includes a plate 37 fixed to the outer end 38 of the shaft 35, a second plate 39 rotatably mounted upon the bushing 40 through which the shaft 35 extends, a torsion spring 41 interconnecting the plates 37 and 39, and a laterally bent lug 42 forming a part of the plate 37 which lies between opposite ends 43 and 4A of a recess formed in the peripheral portion of the plate 39.

A flexible wire 50 is secured at 51 to the end of a radially extending arm 52 formed in the plate 39 and is conducted upwardly to a point on the instrument board of the vehicle through a flexible conduit'53, where adjustment of the wire causes the plate 39 to move wise direction to serve to yieldingly resist opening movement upon its-pivotal support.

When the plate 39 is in the position shown in Fig. 5 the shoe 36 will assume the position shown in full lines in Fig. 8, and the valve E is free to operate in its normal capacity.

When, however, it is desired to choke the carburetor as in starting with a cold motor, the plate 39, by operation of the flexible wire, is caused to move clockwise (see Fig. 5) until the edge 43 of its recessed portion abuts the lug 42. During this movement of the plate 39 the plate 37 and the shaft 35,'by virtue of thespring ll, will rotate in a clockring the shoe 36 to the dotted line position shown in Fig. 8, thus securely holding the valve E closed so that as the engine turns over an extremely rich fuel mixture will be drawn into the engine manifold.

Immediately upon the firing of the engine the driver will cause the wire 50 to be moved toward its normal running position (shown in Fig. '5) but not so far as to cause the shoe 36 to be elevated to the position shown in full lines in Fig. 8. The spring 41 may thus of the valve-E by causing the shoe to bear against the valve. I thus obtain a diminished a-ir flow to the induction chamber A during that period in which the engine is warming up. When the engine has arrived at normal running temperature the choke is returned to that position shown in the drawings.

By th1s means I have provided a choke .anddash control which acts directly upon the automatically operating air valve and which when employed as other than a complete choke, as when warming up, the engine maintains the increased fuel discharge in proper proportion to engine demand. This is not true of the ordinary choke and-dash control which consists of a valve placed in the air inlet F and which provides duringstarting and warming up a fixed restriction to the flow of air, regardlessofengine demand.

'Another feature of my improved carburetor comprises a diaphragm designated at increased. This has been due undoubtedly to the short limits within which a flexible metal diaphragm may freely move.

I employ a diaphragm M constructed of fabric which has been rendered air and fluid tight, the under surface of which bears directly upon a flat plate 50 having a depending skirt formed at its edges for confining one end of. a compression spring 51, the other end of which bears against a ring 52 carried by the valve housing. -When the diaphragm is depressed the plate 50 may bear directly against the valve to cause the valve to open.

Aside from possessing the advantage of a directly proportional application of the differential in pressures on the opposite sides of the diaphragm to the valve L I have found that a diaphragm so, constructed operates with maximum efiiciency for a greater time than that of the metal dlaphragm. This latter advantage is probably .a metal diaphragm subjected to constantly changing stresses takes a set and thereafter fails to properly perform if the constantly fiexin diaphragm doesnot'crystallize and crackdiefore that time has arrived.

In operation my improved carburetor as above setforth, immediate.

brings about, and smooth acceleration of the vehicle free of the tendency of the engine to cough for want of suflicient accelerating aid at both theinitial movement of the vehicle and the acceleration from an intermediate to a higher speed. This is attributed to the accelerating mechanism including the air reservoir 10.

of the engine the driver may properly cholge the carburetor and control the quantity 0 fuel mixture necessary for warming up the engine with the assurance that the increased discharge of fuel mixture will maintain its adjusted relationship to engine demand as the demand increases or decreases with engine speed or load fluctuations. 7

The improved diaphragm M removes all possibility of variation in fuel valve operation as it approaches its limits of normal operating range and lends unusually long an efficient lift to this important element of the carburetor. i

I claim: I

1. In a carburetor, an induction. passage adapted for communication at one endwith due to the fact that During the initial starting and warming up the intake manifold of an internal combustion engine and having its opposite end open to atmosphere, a spring-pressed air valve disposed in said passage for maintaining a substantially constant depression in that portion of the passage anterior thereto, a fuel nozzle discharging into said induction passage by virtue of said depression therein, means operable at will from a point remote from the carburetor for augmenting the tendency of said spring-pressed valve to close, and spring a means associated with said operable means for yieldingly holding said operable means position relative to said air valve,

.virtue of said depression therein, means operable from a point remote. from the carburetor for limiting the opening movements of said air valve, at will, and spring means asso-, ciated with said operable means for yieldingly holding said operable meansin any of its air valve limiting positions relative thereto, whereby a choking effect is produced in the induction passage to cause an enrichedfuel mixture asin starting.

3. In a carburetor, an induction passage adapted for communication at one end with the intake manifold of an internal combustion engine and having its opposite end open to atmosphere, a spring-pressed air valve disposed in said passage for maintaining a substantially constant depression in that portion of the passage anterior thereto, a fuel nozzle discharging into said induction passage by virtue of said depression therein, means operable at will from a point remote from the carburetor for holding said air valve closed to cause a very rich fuel charge to be drawninto the engine manifold as when starting the engine, and spring means associated with said operable means for holding said operablemeans immovable at-a desired distance from said air valve. Q

4. In a'carburetor, an induction passage ada ted for communication at one end with the intake manifold of an internal combustion engine and having its opposite end open to atmosphere, a spring-pressed air valve .dis-

posed in said passage for maintaining a substanti'ally constant epression in that portion of the passage anterior thereto, a fuel -nozzle dischargmg into said induction passage by virtue of said depression therein, aspring pressed shoe including spring means and havmg'a part thereof adapted to bear upon said air valve to augment the tendency of the air valve to close, and means associated with the shoe and said spring means adaptedfor man ual operation for holding the shoe entirely clear of the valve throughout its full range of movement, for holding the shoe immovable against the air valve to prevent valve movement, or for yieldingly holding the shoe immovable at a desired distance from the valve by said spring means to limit valve movement at will. a I

5. In a carburetor having a fuel nozzle dependent in its operation upon the subjection of its delivery orifice to adepression derived from engine manifold suction, a fuel chamber communicating with said fuel nozzle, one wall of said chamber comprising a flexible liquid and air tight fabric diaphragm, the outer side of which is subjected to atmospheric pressure, and a f e valve for admittingfuel to the chamber, said valve being p'ositioned in such a manner as to open when said diaphragm flexes downwardly by the differential in pressure between the chamber and atmosphere.

6. In a carburetor having a fuel nozzle dependent in its operation upon the subjection of its delivery orifice to a depression derived from engine manifold suction, a fuel chamber communicating with said fuel nozzle, one wall of said chamber comprising a flexible liquid and air-tight fabric diaphragm, the

outer side of which is subjected to atmospheric pressure, a fuel valve for admitting fuel to the chamber, said valve being positioned in suchva manner asto open when said diaphragm flexes downwardly by the differential in pressure between the chamber and atmosphere, and resilient means for resisting the movement of said diaphragm by atmospheric pressure.

7. In a carburetor having an induction passage adapted for communication with the intake manifold of an internal combustion engine, a fuel nozzle, a fuel chamber for supplying fuel to the, nozzle, a main fuel supply tank, a passage for conducting fuel from the tank to the chamber, means operable upon a sudden fall in'manifold suction for automatically causin an increase in the'fuel discharge from said nozzle, a reverse fuel reservoir, and means cooperating with said last named means for supplying reserve fuel from said reservoir to said fuelchamber as when.

the fuel conducting passage is subjected to back suction due to inertia of fuel therein.

8. In a carburetor having an induction chamber wherein an automatic air valve is employed to normally maintain a condition of constant depression in the induction chamber by controlling the ingress of air thereto, the combination of accelerating mechanism for momentarily causing a closing movement ofsaid air valve to increase induction chamber depression and a fuel reservoirhaving an air cushion over the level of fuel therein for a momentary closin valve to increase in uctlon chamber depresassuring thesuppl of fuel for dischar 0 into the induction c amber regardless of t e feeding of fuel thereto from the normally used fuel source.

9. In a carburetor including an induction chamber, an automatic air valve therein normally maintaining a constant depression in the induction chamber by controlling the ingress of air thereto, means operable upon a sudden fall in manifold suction for causing movement of said air sion, and a fuel reservoir having an air cushion over the level of the fuel therein for assuring a supply of fuel for discharge in the induction chamber regardless of the feedin of the fuel thereto from the normally use I source. a

10. In a carburetor chamber, an automatic air valve therein normally maintaining a constant depression in the induction chamber by controlling the ingress of air thereto, a fuel nozzle, a fuel chamber for supplying thereto, means operable upon a sudden fall in manifold suction for causing a momentary closing movement of said air valve to increase induction chamber depression, and a reserve fuel reservoir having an air cushion over the level of the fuel therein for assuring the supply of fuel for discharge from said reservoir through said nozzle into the induction chamber regardless of the feeding of fuel thereto from the normally used fuel source.

In witness whereof, I hereunto subscribe I my name this 15th day of July, 1929.

ROBERT F. vBRACKE.

including an induction 

